Pneumatic granule supplying apparatus



Sept. 9, 1941.

O. V. MCGREW PNEUMATIC GRANULE SUPPLYING APPARATUS Filed Aug. 21, 1939 2Sheets-Sheet l O. V. MCGREW PNEUMATIC GRANULE SUPPLYING APPARATUS 2sheets-sheet 2 Sept. 9, 1941.

Filed Aug. 2l, 1939 Patented Sept. 9, 1941 PNEUMATIC GRAN ULE SUPPLYINGAPPARATUS Orville V. McGrew, Chicago, Ill.

Application August 21, 1939, Serial No. 291,238-

1 Claim.

This invention relates to a pneumatic granule supplying apparatus, andmore particularly to an apparatus for embedding granules in plasticcoating compositions.

In my Patent No. 2,145,027, issued September 8, 1938, is disclosed acomposition of asphalt and cork and a method of applying it to surfacesin coatings of appreciable thickness. In my copending application SerialNo. 281,266, iiled June 26, 1939, is disclosed a drying oil compositionwhich may be applied in a similar manner.

In the case of either such compositions, or in other plastic coatingcompositions, it is frequently desirable to apply a coating of roongtype granules to the plastic material while itis still in a plasticstate. The present invention relates to an apparatus adapted to embedsuch granules in the plastic coating a suitable distance.

'I'he invention is illustrated in the drawings in which Figure 1 is aside elevation, partly broken away, of the apparatus; Figure 2 is an endelevation of the lower portion of the hopper and appurtenances; Figure 3is a sectional elevation, partly in section, taken along the line 3 inFigure 2; Figure 4 is a sectional elevation, partly in section, takenalong the line 4 in Figure 2; Figure 5 is a view, partly incross-section, of the ejector nozzle; and Figure 6 is a cross-section,ltaken on the line 6 in Figure 5.

The device consists of a hopper I having sloping walls II at the bottomconverging to an orice I2. A nozzle I3 is positioned within a largerpipe I4 just below the orice I2. The nozzle comprises a tubular portionI which is threaded at each end. The base of the tubular portion isscrewed into a bushing I6 set in an end wall I l of the pipe. A couplingI8, adapted to be connected to an air hose, is secured to the bushingoutside of the pipe. A collar I 9 is secured over the front end of thetubular portion I5 leaving a small space 20. The collar I9 is likewiseprovided with an orice 2| of slightly smaller diameter than the orice 22in the tube I5. The pipe I5 shown is 1/8 inch standard pipe and theopening 2| is suitably 5/32 inch in diameter, or larger, up to thediameter of the pipe. The positioning of the opening 2I with respect tothe mouth I2 of the hopper is quite critical. If it is set too far back,or if the opening 2| is improperly adjusted, the granules will not feedproperly from the hopper I0, either not being drawn along by the air orelse permitting the air to by-pass through the hopper. The respectivepositions shown in Figure 4 are ideal for granules of the 55 .itself istapped for a 3A inch pipe.

ordinary roofing size (10 to 20 mesh) and for the 2-inch standard pipe Mand the 11/2 inch standard pipe I2.

Pipe I4 is connected to the line 25 leading to the cyclone 26. Thecyclone is provided with an opening 2l at the top and a smaller opening28 `at the bottom, the latter being connected to the body of thecyclone, as shown in Figure 5, by the orifice 29. The opening 28, whichforms the nozzle, in addition is provided with a further opening 30within which is seated an elbow 3| connected to an independent air line32. The elbow is tapped on the inside for a f8 inch pipe 33.

As shown in Figure 6, the 1A; inch pipe is 1% inches long. One end of itis brazed closed and drilled with a 511g inch hole 34. The end of thepipe 33 is 1% inch from the opening 28 which 'Ihe opening 29 is tappedfor a l-inch pipe.

'I'he passage of air to the nozzle 28 and through the granule line iscontrolled by the diaphragm valve 50, shown in Figure 3. This comprisesa exible diaphragm 5I, held in a chamber 52 with a spring 53 inengagement with the diaphragm, which ordinarily holds the plunger valve54 in engagement with the valve seat 55, thereby shutting off the airfrom the line 25. A plunger 56 adjacent to the nozzle (Figure 1)controls the air in the auxiliary line 32, and, when this plunger ispressed, air passes through the line 32 from the air inlet 40. As soonas the air passes through line 32 the. pressure in chamber 52 isreduced, thereby opening the valve 54. In securing this eiect theopening of valve 4I is suitably adjusted to control the speed with whichthe diaphragm valve acts. The openings 51 assist in making this controlmore sensitive and also decreases the sensitivity of the diaphragm valveto variations in the line pressure from the compressor. As soon as thevalve 56 is released, however, the

pressure in chambers 5I and 52 equalizes and thel spring 53 closes valve54.

In operation of the device the hopper I0 is iilled with granules of theproper size, the necessary air connection is made, 'and the plunger 56is pressed. This produces a blast of air at 28 and shortly thereafter,the time being regulated by adjustment of the valves 4I, 42 and 43,associated with lines 32 and 25, air is admitted through line 25 andcommences to carry granules with it. The granules pass into the upperpart of the cyclone 26 and are drawn downwardly and ejected from thenozzle 28, the dust in the meanwhile separating therefrom and passingout of` the opening 21. Granules are ejected with considerable force andembed themselves sumciently to produce a very satisfactory bindingaction in the plastic material to which they are applied.

The amount of air pressure employed on the line 40 may vary considerablydepending upon the type of granules, the type of plastic, and the lengthand size of hose line 215. Under most circumstances a pressure 0140 lbs.per square inch is most satisfactory. If the hose is too long, it may benecessary to throttle the pressure upon the line 32 because of theexcessive pressure drop throughout the line 25.

I claim:

A granule applying apparatus comprising a hopper, a flexible hoseconnecting the hopper and a centrifugal cyclone device, a nozzle.pneumatic means for forcing granules from the hopper into the hose, andindependent pneumatic means supplying air to the nozzle, said cyclonedevice comprising a chamber having a large opening at one end and arelatively small opening communicating with the nozzle at the other endand shaped to produce rapid centrifugal motion of the pneu, matic streamcarrying the granules therein.

ORV'ILLE V. MCGREW.

